Flash boiler



June 25, 1968 JOHNSON ET AL 3,389,692

FLASH BOILER 2 Sheets-Sheet 1 DON E. JOHNSON 5L MO .4. PORTQ? mvsw'rons.

Filed Pep Arron/airs.

June 25, 1968 D. E. JOHNSON ET AL 3,389,692

FLASH BOILER Filed Dec. 15. 1966 2 Sheets-Sheet 2 oo/v JOHNSON 61440 A.FORTE? INVENTORS.

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United States Patent 3,389,692 FLASH BOILER Don E. Johnson, 524 W. 6thDrive, and Elmo A. Porter, 1025 E. Jarvis Ave., both of Mesa, Ariz.85201 Filed Dec. 13, 1966, Ser. No. 601,455 11 Claims. (Cl. 122-41)ABSTRACT OF THE DISCLOSURE A flash boiler including a series ofconcentric tubular members alternately interconnected to provide twoflow paths, one path receiving feedwater from the radial outer portion,which is discharged as steam from a central tube, the other pathreceiving hot gases which pass a chamber where the water is flashed intosteam and enter the other flew path around the central tube, each of thepaths having a helical baflie therein, the baflles being oppositelywound in the two flow paths.

This invention pertains to a boiler for converting water intosuperheated steam.

This invention provides an extremely fast acting flash boiler in whichthe rate of heat transfer is accelerated considerably over that ofdesigns of the prior art. With this boiler, water is converted to steamin an extremely short period of time, even when the boiler is started upfrom a cold condition. The boiler also is very compact, light and simpleto construct.

These results are accomplished through an arrangement of concentriccylinders that define a series of adjacent annular passageways throughwhich the water and the hot burner gases are conducted. The water andheated gases are in alternate layers, circulating in opposite axialdirections. Helical baflles are included in the concentric passageways,lengthening the flow paths and providing a swirling effect to increasethe heat transfer. The water enters from the outside and is dischargedas steam from an axial passageway, while the hot gas enters near thecenter of the unit and is discharged adjacent its periphery. The wateris vaporized at a flash plate positioned at the inlet for the burnergases.

An object of this invention is to provide an improved flash boiler.

Another object of this invention is to provide a flash boiler that willconvert water to steam in a very short period of time.

A further object of this invention is to provide a boiler that iscompact and light in weight.

An additional object of this invention is to provide a boiler that canbe manufactured easily and at a low cost.

Yet another object of this invention is to provide a boiler that can beassembled from desired numbers of modular sections to provide differentsteam-generating capacities.

These and other objects will become apparent from the following detaileddescription taken in connection with the accompanying drawing in which:

FIGURE 1 is a longitudinal sectional view of the boiler of thisinvention;

FIGURE 2 is a transverse sectional view taken along line 2-2 of FIGURE1;

FIGURE 3 is a transverse sectional view taken along line 33 of FIGURE 1;

FIGURE 4 is an enlarged fragmentary longitudinal sectional view of theconcentric cylinders forming a portion of the boiler of the invention;and

FIGURE 5 is a fragmentary perspective view of the members connecting tothe separating plate adjacent the gas inlet, removed from the othercomponents of the boiler.

3,389,692 Patented June 25, 1968 ice concentric tubes or cylinders. Thisincludes a centraltubular member 11 at the axis of the unit, spacedoutwardly from which is a cylinder 12. An additional cylinder 13circumscribes and is spaced from the cylinder 12. Beyond the cylinder 13is the next cylinder 14, followed by the outer cylinder 15. This definesa series of passageways, one of which is provided by the bore of theinner cylindrical member 11 and the others of which are annular in crosssection and formed by the spaced concentric cylinders. Thus, there is apassageway 17 between the members 11 and 12, while the latter member andthe next cylinder 13 provide an annular passageway 13. Passageway 19 islocated between the cylinders 13 and 14, and an outer passageway 20 isformed by the cylinders 14 and 15.

Helical bafiles are provided in the annular passageways, serving both todirect the flow of fluid in the passageways and to hold the cylindricalmembers in their spaced concentric relationship. The baffles are flatstrips of metal wound to a spiral form and closely fitted at theperipheries of the cylindrical members. The innermost baflle 22 is inthe passageway 17, while outwardly of it is the baflle 23 in thepassageway 18. Baflles 24 and 25 are disposed in the passageways 19 and20, respectively. The helices in the passageways 17 and 19 are wound inthe opposite direction. Similarly, the baffles 23 and 25 in thepassageways 18 and 20 provide helices wound in two different directions.

A connection is provided between the passages 17 and 19 through an endmember 26 located at the left-hand of the unit as illustrated inFIGURE 1. The connecting member 26 is generally in the shape of half ofa toms, providing a smooth bend between the two passageways. The member26 also closes the end of the passageway 18.

The passageways 18 and 20 also are joined by means of four straighttubes 27 which connect to the passageway 20 adjacent its end wall 28. Asbest seen in FIGURE 2, the tubes 27 extend through the passageway 19,but are sealed relative to it. They enter the inner passageway 18 in asubstantially tangential relationship. An inlet is provided at theopposite end of the passageway 20 by a tube 29 that connects to thecylinder 15.

The periphery of the outer cylinder 15 is wrapped with a high-tensilewire 30. The wire 30 is wound in a continuous length around thecircumference of the cylinder 15 with its adjacent turns in contact,thereby providing the outer cylinder and the entire boiler unit with aresistance to bursting forces. This allows the cylinder 20 and the othertubular elements as well to be made of relatively lightweight material,because the wrapped exterior of the outer cylinder provides the unitwith adequate strength and renders it perfectly safe. There is anadditional wrapping 31 over the wire 30, this being made up of fibers ofinsulating material. The first portion immediately over the wire 30 isof asbestos fibers, while toward the outer part of the wrapping 31 glassfibers are utilized. The fibers in the wrapping31 also have high tensilestrength properties and assist the wire 31} in resisting bursting forcesin the boiler. The exterior of the boiler unit is encased in alightweight metal shell 32.

' The right-hand ends of the cylinders 12 and 13, as the device is shownin FIGURE 1, project outwardly beyond the corresponding ends of thecylinders 14 and 15. An annular plate 34 extends over the ends of thecylinders 12 and 13 to close the passageway 18. The inner edge of theplate 34 is coterminous with the inner periphery of the cylindricalmember 12, while the outer edge projects radially beyond the cylinder13. A tubular element 35 connects to the outer edge of the plate 34, andspaced exteriorly of this is an additional tubular member 37.

3 Opposite theplate 34, the right-hand end of the outer passageway 20 isclosed by an annular plate 38 that extends beyond the cylinder to theouter tubular member 37. Consequently, the passageway 19 between thecylinders 13 and 14 connects to a passageway 39 defined by the plates 34and 38 and the tubular members 35 and 37; A tubular outlet stack 40connects to the right-hand end of the passageway 39. Extending throughthe plate 34 adjacent its inner edge are four straight tubes 42. Theirdiameters are substantially equal to the width of the passageway 18 towhich they connect. The tubes 42 enter a housing 43 opposite an end wall44 that acts as a flash plate when the boiler is in operation. The flashplate is dome-shaped and has a central protuberance 45. The central tube11 of the boiler extends to the'right beyond the cylinders 12 and 13through the axis of the Walt 46 of the housing 43 inwardly of the tubes42. Thus, there is a connection between the passageway 18 and the boreof the tube 11. This is effected by the tubes 42 that extend through thewall 46 into the housing 43 adjacent the outer edges of the dome-shapedwall 44. The curved configuration of the wall 44 of the housing,together with the central protuberance 45, provides a smooth bend informing the connection to the tube 11.

A wall 48 is provided outwardly of the assembly of the housing 43 andthe tubes 11 and 42, curving to the inner edge of the end plate 34.Insulation 49 is provided between the wall 48 and the tubular member 35.The right-hand end of the wall 48 connects to a burner 50 for generatingheated gases. These gases, therefore, flow from the burner into thechamber defined by the wall 48. The gases travel past the flash plate 44and around the four tubes 42 into the inlet of the passageway 17. Theyare conducted to the left as the device is illustrated through thepassageway 17, being given a helical flow pattern by the baffle 22. Whenthe end of the passageway 17 is reached, the member 26 directs the hotgases smoothly back into the passageway 19 so that the axial directionof travel is reversed. Again, the baffle 24 causes the gases to swirl ina helical fashion as the passageway 19 is traversed. Because the bafile24 is wound oppositely from the baffle 22, the rotational direction ofthe gas remains the same even though its axial direction has beenreversed. At the end of the passageway 19, the gases then flow into thepassageway 39 and out through the stack 40. By discharging the gasesaround the inlet from the burner, the heat losses at this area areminimized because there is a lower temperature differential across thewall around the inlet than would be the case if the wall were exposed toatmosphere.

Water, which normally comes from a condenser, enters the unit from thetube 29, flowing into the passageway 20. The baflle 25 directs the waterin a helical flow pattern as it moves leftward in the passageway as thedevice is shown. When the end of the passageway 20 is reached, the watermoves through the four tubes 28 that connect to the passageway 18. Atthe latter location, the water reverses its travel and moves to theright, again in a helical pattern. The baffles and 23, being oppositelyWound, maintain the same rotational direction of flow for the waterdespite its reversal in axial direction. At the end of the pasasgeway18, the water is conducted through the four straight tubes 42 into thehousing 43. At this location, the water flows around the inner surfaceof the baflle plate 44, where it flashed into steam. There is a pressuredrop and a temperature rise as the water moves across the hot flashplate 44 and dry steam is produced. The steam then moves axially to theleft through the central tube 11 in which it becomes superheated.

The unit is proportioned so that a constant cross-sectional area isprovided throughout the flow path of the water, while there is a largerarea at the central tube 11 that conducts the steam. There is a muchnarrower nadial spacing between the cylinders 14 and 15 than thatbetween the cylinders 12 and 13. The greater circumference of theannular space 20, however, results in the same flow capacity as that ofthe passageway 18. The tube 11 may be around 25% greater incross-sectional area than that of the water passageways.

With the water and hot gases flowing in alternate annular passagewaysthrough the boiler unit, there is maximum opportunity for heat transferto the water as it travels from the intake to the flash plate. By thetime it reaches the flash plate, the water temperature has been elevatedand it is nearly to the point of vaporization. The water is flashed intosteam at the hottest portion of the unit where the gases coming directlyfrom the burner play on the exterior of the flash plate to cause thevaporization. The unit also provides for heat transfer to the steam toaccomplish the superheating as the gases immediately following thecontact with the flash plate flow around the steam outlet at the axis ofthe unit.

This construction provides an exceptionally high rate of heat transferfrom the hot gases to the water to effect the conversion of the waterinto steam. Heat is conducted rapidly through the relatively thin wallsof the tubular members 11, 12, 13 and 14 for heating the waterthroughout its travel through the boiler. The fact that the water andthe gases both are traveling in helical flow patterns means that theeffective area for heat transfer is large even though the boiler unit iscompact in size. The hot gas is made to lose a maximum amount of heatduring its flow through the boiler by virtue of the spiral flow and thedouble pass that the gases make. The helical baffles 22, 23, 24 and 25not only spacethe tubular members apart but also provide an additionalmeans to transmit heat from the gas passageways to the waterpassageways.

While described above as a boiler for generating steam, the unit of thisinvention has general applicability as a heating device. It isparticularly well suited to serve as a water heater, in which eventthere is the same general arrangement of parts, but the burner will notimpart suflicient heat to the water to effect vaporization.

Despite the high efiiciency of the unit, it is readily manufactured at alow cost and can be made of lightweight materials. Moreover, it can bemade in modules that can be assembled in different numbers to vary thesteam-generating capacity. By eliminating the end members 26 and 28 fromthe unit shown, additional numbers of concentric cylinders may be addedto lengthen the boiler. The outermost set of concentric cylinders willbe closed by the members 26 and 28. The flow through the unit will bethe same as before but the length of travel of the gases and water willbe greater, and a larger, amount of water can be converted to steam.

The foregoing detailed description is to be clearly understood as givenby way of illustration and example only, the spirit and scope of thisinvention being limited solely by the appended claims.

We claim:

1. A boiler device comprising means defining a plurality of concentricpassageways,

said means including an inner central passageway and successive annularpassageways outwardly of said inner central passageway,

means interconnecting alternate one of said passageways so as to definea duality of paths,

baflle means in said annular passageways for providing a helical contourto said passageways,

said baflie means being oppositely wound in adjacent annularpassageways,

a first inlet means connected to one of said paths for introducing hotgases therein,

outlet means for said one path for discharging said gases,

a second inlet means connected to the other of said paths forintroducing water therein,

and outlet means for said other path for discharging steam therefromupon heating of said water in said other path by said hot gases. 2. Aboiler device comprising a central tubularmember,

a plurality. of tubular members concentric with said -.central tubularmember and spaced outwardly therefrom defining a series of annularspaces outwardly of said central tubular member,

means interconnecting alternate ones of said spaces so as to define aduality of paths,

one of said paths being connected to said central tubular member,

a first inlet for said one path at the radial outer portion thereof,

said central tubular member providing an outlet for said one path,

said one path being adapted to receive water at said inlet and todischarge steam at said outlet,

a second inlet for the second of said paths adjacent said centraltubular member,

said second inlet being adapted to receive gases,

said second of said paths having a portion connected to said secondinlet and circumscribing said central tubular member for conducting suchhot gases directly from said second inlet over said central tubularmember,

an outlet for said second path at the radial outer portion thereof fordischarging said gases, and bafile means in said spaces in said one pathand in said second of said paths for cooperating with said tubularmembers to provide helical passageways through said paths.

3. A device as recited in claim 2 in which for each of said paths theconnections between alternate spaces between said tubular members arealternately at opposite ends thereof, whereby flow through said pathsreverses axially of said tubular members at said ends.

4. A boiler comprising a plurality of concentric cylinders with thewalls thereof in spaced relationship thereby to define annular spacesbetween said cylinders,

means interconnecting alternate ones of said spaces for providing aduality of flow paths through said cylinders,

helical bafile means in said spaces for directing fluid in said spacesin helical patterns,

said bafile means in one of said flow paths being oppositely wound fromthe baffie means in the other of said fiow paths,

a housing at one end of said cylinders,

the innermost one of said cylinders connecting to the interior of saidhousing, the second annular space outwardly from said innermost cylinderbeing connected to said housing for providing a connection between saidinner-most cylinder and said second annular space at said housing, saidhousing having an end wall, and an inlet passage adapted for receivingheated gases from a burner,

said inlet passage being connected to the annular space immediatelyoutwardly of said innermost cylinder and extending around said housingfor thereby conducting said gases around said housing and into saidspace immediately outwardly of said innermost cylinder.

5. A boiler comprising a first elongated tubular member,

a housing having a hollow interior,

one end of said tubular member extending into said housing,

a second tubular member circumscribing said first hot tubular member anddefining a first annularv space between said first and second tubularmembers,

said second tubular member having an open end inwardly of said end ofsaid first tubular member, athird tubular member circumscribing saidsecond tubular member and defining a second annular space betweensaidsecond and third tubular members,

said third tubular member having an end inwardly of said end of saidfirst tubular member, means closing said end of said third tubularmember, conduit means interconnecting said second space and said housingthereby to interconnect said second space and said first tubular memberat said housing, a fourth tubular member circumscribing said thirdtubular member and defining a third annular space between said third andfourth tubular members, a fifth. tubular member circumscribing saidfourth tubular member and defining a fourth annular space between saidfourth and fifth tubular members, means interconnecting said fourthspace and said second space thereby to provide a first passagewaydefined by said fourth space, said second space, said conduit means andsaid first tubular member, water inlet means connected to said fourthspace for conducting water through said first passageway, a chamberaround said housing,

said chamber extending to said end of said second tubular member andcommunicating with said first space, means interconnecting said firstspace and said third space thereby to provide a second passagewaydefined by said chamber, said first space and said third space,

and inlet means for said chamber for receiving heated gases to beconducted through said second passageway for heating water flowing insaid first passageway and converting said water to steam at saidhousing.

6. A device as recited in claim 5 in which said housing includes an endwall opposed to said end of said first tubular member and said conduitmeans and in the direct path of gases received from said inlet for saidchamber,

said end wall having a dome-shaped contour and including curved surfacemeans for directing said water from said conduit means to said firsttubular member.

7. A device as recited in claim 5 including in addition filament meanscircumscribing said fifth tubular member for providing a resistance tooutward forces on said tubular membersj 8. A device as recited in claim5 including in addition passage means connected to said third space andcircumscribing said chamber for conducting said heated gases around saidchamber, said passage means having an outlet therefrom for dischargingsaid gases.

9. A device as recited in claim 5 including in addition a helical baffiein each of said spaces for providing a rotational flow pattern in saidspaces.

10. A device as recited in claim 9 in which said bafiles in said firstand third spaces are oppositely wound,

said bafiles in said second and fourth spaces are oppositely wound,

and said interconnecting means for said first and third spaces and saidinterconnecting means for said second and fourth spaces are at the endsof said spaces, whereby the direction of rotation of flow is the same insaid first and third spaces, and the direction of rotation of flow isthe same in said second and fourth spaces. 11. A boiler devicecomprising a central tubular member,

a plurality of tubular members concentric with said central tubularme'mberandspaced outwardly therefrom defining a series of annular spacesoutwardly of said central tubular member, means interconnectingalternate ones of said spaces so as to define a duality of paths,

one of said paths being connected to tubular member, a first inlet forsaid one path at the radial outer portion thereof,

said central tubular member providing an outlet for said one path,

said one path being adapted to receive water at said inlet and todischarge steam at said outlet, a second inlet for the second of saidpaths adjacent said central tubular member,

said second inlet being adapted to receive hot gases, an outlet for saidsecond path at the radial outer portion thereof for'discharging saidgases, bafile means in said spaces for cooperating with said saidcentral 8 tubular members to provide helical passageways through saidpaths, and a hollow chamber connected to the annular space of said onepath adjacent said central tubular memher for receiving the flow 'in'said one path,"

said hollow chamber including" arcuate: surface means for directing saidflow into said'central tubular member, said second inlet communicatingwith said hollow chamber on the exterior thereof for imparting heat tosaid hollow chamber and causing water in said one path to flash in-tosteam,

References Cited UNITED STATES PATENTS 2,832,320 4/1958 Thome et al.122-161 XR KENNETH W. SPRAGUE, Primary Examiner.

